THE LIVING WORLD

1.  INTRODUCTION

• Biology is the science of life forms and living processes. in nature there is sharing of similarity among living organisms both horizontally and vertically. That is all present day organisms are related to each other and also to all organisms that ever lived on this earth.
• Ernst mayr (1904-2004) an evolutionary biologist who has been called ‘The Darwin of the 20^th century’. He almost single handedly made the origin of species diversity the central question of evolutionary biology. He has also given definition of a biological species.
• Life is a unique, complex organisation of molecules expressing itself through chemical reactions which lead to growth, development, responsiveness, adaptation and reproduction. The various traits shown by living beings are as follows:

2.  CHARACTERSTICS OF LIVING
Growth

• Growth is based upon twin characteristic of increase in number and size.
• In case of plants growth is a continuous process because of the presence of meristematic tissue.
• In case of animals, growth occurs only up to a certain age but replacement of cells do take place. e.g. RBC’s which are replaced after every 120 days.
• Growth depends upon a balance between catabolism and anabolism., if rate of anabolism is greater than rate of catabolism, growth will occurs and if rate of catabolism is greater than rate of anabolism then de-growth will occur.
• Growth can also be defined as sum total of protoplasmic and apoplasmic substances synthesized within cell.
• Non-living thing such as mountains, sand dunes also increase in size but the basic difference is, growth in case of living beings is intrinsic and in case of non-living things, it is extrinsic secondly there is no difference between growth and reproduction in case of unicellular organisms.
  So, growth cannot be considered as a definite criterion for being living.

Reproduction

• Reproduction is a biological process which results in production of young ones which are similar to their parents (sexual reproduction). But in nature there is asexual reproduction also like spore formation (in algae, fungi), fragmentation (in algae, fungi, moss protonema). Regeneration (Planaria), Budding (yeast, hydra).
• But in nature, we have various examples where living organisms are not able to produce offsprings (e.g., worker boney bee, childless couple, mule and hinny).
• It is difficult to distinguish between growth and reproduction in case of unicellular organisms such as bacteria.
  So, reproduction cannot be considered as a definite criteria for being living.

Metabolism

• All-living organisms show metabolism.
• Metabolic reactions can be demonstrated outside the body in cell-free system, but it is neither living nor non-living.
• Metabolism is sum total of all in biochemical reactions taking place inside the body. These reactions are important for survival of individual.
• Metabolic reactions can be replicated under in vitro conditions but these reactions are living and process is not living because a particular cellular organization is require so that products of reaction can be properly mobilized and for this, cellular organization is required a thus metabolism along with cellular organization is definite criteria for living.

Consciousness

• It is ability to sense environment and mount suitable response. Environmental stimulus can be either biological, physical or chemical e.g. depending upon day length, plants show flowering (photoperiodic response in case of animals, seasonal breeders. e.g. of biological stimulus is viral infection, and immune response. Thus consciousness is considered as a definite criterion for being living.
• Living Beings are self-replicating ever-evolving organisms with capacity to self-organize and respond to environmental stimulus.
• The underlying interaction between constituent cells of tissue results in emergent properties which were not earlier present in constituent cells and this is responsible for life.

3.  DIVERSITY IN THE LIVING WORLD

• There are millions of living organisms such as plants, animals, bacteria and slime moulds etc.. Currently 1.7 million living organisms are known to the science. About 1.2 million of species of animals and 0.5 million species of plants have been studied described and provided names for identification. The single group of insects, however, outnumbers all the plants. This group contains over 0.75 million species. Every year about 15,000 new organisms are discovered. Thousands are still unknown and are yet to be identified and described. It is practically impossible to study each and every individual. Also, it is difficult to remember their names, characters and uses. However, biologists have devised techniques for identification, naming and grouping of various organisms depending upon the extent of similarities and differences as per certain rules.

 4.  SYSTEMATICS

• Scientists who study and contribute to the classification of organisms are known as systematists or taxonomists, and their subject is called systematics(Gk. Systema: order or sequence) or taxonomy (Gk. Taxis: arrangement; nomos: law). The terms ‘systematics’ was coined by C. Linnaeus.
• Generally, the terms such as classification, systematics and taxonomy are used interchangeably but some taxonomists, like Simpson (1961), relate them to separate fields. He considers systematics as the study of the diversity of organisms and all their comparative and evolutionary relationships, based on comparative anatomy, comparative ecology, comparative physiology and comparative biochemistry. He regarded classification as a subtopic of systematics that deals with ordering of organisms into groups and taxonomy as the study of principles and procedures of classification.
• Theophrastus (370-285 BC), often referred to as ‘Father of Botany’, in his book Historia Plantarum, classified plants on the basis of their habit, form and texture into four categories-­trees, shrubs, undershrubs and herbs. He gave name and description of 480 plants in his book.
• An Indian worker Charaka (first century A.D.), regarded the father of Ayurveda, listed about 340 plants and about 200 animals in his book Charaka Samhita on Indian Medicine.
• In the late 17th century, John Ray, an English naturalist coined the term species for a group of morphologically similar organisms and also tried to differentiate between genus and species. The terms, ‘monocotyledons’ and ‘dicotyledons’ were also coined by him. Based on extensive travel all over Europe, he described more than 18600 plants and animals in his book Historia Generalis Plantarum.
• Another significant period for taxonomy was that of Linnaeus. Carolus Linnaeus (1707-1778), a Swedish naturalist, often referred to as ‘Father of Taxonomy’ published Systema Naturae(1758) and described 4326 species of animals. His treatise, Species Plantarum(1758) contained description of 5900 species of plants and these were arranged according to his system of classification based on sexual character. Linnaeus also introduced a system of nomenclature of plants and animals known as the Binomial Nomenclature.
• In earlier systems of classification, only external morphological observable characters with the help of unaided eye formed the sole basis of classification of plants and animals. The characters like root modification, leaf venation, floral structures, number of cotyledons, etc. were used in classification of flowering plants. Right from Aristotle to Linnaeus, every one considered only limited features in the classification of organisms. As a result, the diverse living organisms in nature were placed into limited number of groups. This phase of taxonomy led to the development of artificial system of classification. Later, the organisms were classified on the basis of natural affinities (i.e., the basic similarities in the morphology). This phase represented the classical taxonomy and produced natural system of classification. At the opposite end of the taxonomic spectrum, other biologists assigned taxonomic affinity based on evolutionary as well as genetic relationships among organisms besides morphology. They ignored the morphological similarity or difference. This resulted in development of phylogenetic classification or cladistics (Gk. klados-branch, clados – branch).
• Cladistics classifies organisms according to the historical order in which the evolutionary branches arose. This led to the emergence of new systematics or biosystematics.

New Systematics (Neosystematics, Biosystematics)

• It is a concept of systematics that considers a species to be the product of evolution. It takes into consideration all the known characteristics of organisms and all the known evidences from different fields of biology. The concept of new systematics was developed by Sir Julian Huxley in 1940. The important features are:
• Species are not isolated. They are related amongst themselves by common descent and differ from them due to accumulation of different variations.
• Main stress is laid upon subspecies and populations instead of species. It has given rise to the concept of population systematics.
• Statistical data are used to determine primitiveness or advancement of a species.
• Morphological definition of species is replaced by biological definition. Besides morphology, biosystematics or new systematics considers traits from cytology, genetics, ecology, biochemistry and physiology. This has led to the origin of many branches of systematics like: Morphotaxonomy (based on morphological traits), Cytotaxonomy (based on cytological study), Karyotaxonomy (based on nucleus and chromosomes), Biochemical taxonomy (based on biochemical studies), Chemotaxonomy (based on specific chemicals like secondary metabolites), Numerical taxonomy (using statistical methods in taxonomy) and Experimental taxonomy (based on experimental determination of genetic interrelationships and effect of environment).
• A large number, sometimes thousands of specimens are studied to record variations before deciding the limits of species.
• The basic unit in new systematics is population.
• The new systematics is scientific and very useful academically as well as economically.
• Numerical taxonomy is also called pheneticor Adansonian taxonomy(Adanson, 1763). Turril (1938) used the term Omega ( ) taxonomy for biosystematics or neosystematics. His Alpha ( ) ­taxonomy (Turril, 1938) deals with collection and identification of organisms on the basis of gross morphology, compilation of flora and monographs.

Basics in Classification

• Classification means the ordering of organisms into groups. The branch of science that deals with the study of principles and procedures of biological classification is called taxonomy(A.P. de Candolle), 1813). Taxonomy enfolds the following fundamental elements:
  • Characterisation & Identification: To identify and characterize an unknown organism by comparing it with known organism. Identification is determining the correct place in a system of classification and finding out the correct name of an organism. It is done with the help of keys. This is carried out for an organism by determining its similarity with an already known organism. Suppose there are three plants say a, b, All represent different species. Another plant, say d resembles b. The recognition of the plant d as identical to the already known plant b is its identification.
  • Nomenclature (L. nomen: name; calare: call): It is the science of providing distinct and proper names to organisms as per the established universal practices and rules so that they can be easily recognized and differentiated from others.
  • Classification: Classification is the arrangement of organisms into groups on the basis of their affinities or relationships. It involves the placing of a kind of organisms or a group of different kinds of organisms in particular categories depending upon the system of classification but in conformity with nomenclature system.

Nomenclature

• The science of giving names to living beings is called Two types of names are given to the organisms, common and scientific.         

Common or Vernacular Names

• Naming of organisms has been started with the appearance of language in human civilization. Common names are local names, which are given to the animals and plants in a particular language and region of the world by local persons. The vernacular or common names are based on some peculiarity of the organisms. They are brief and easier to pronounce and remember by the residents of an area. Even then the vernacular names cannot be used by biologists due to the following reasons:
• Common names differ from region to region and language to language. · An organism may have several names in a given language.
• A common name may have different meanings in different areas.
• A wrong common name cannot be easily corrected.

Scientific or technical names

• Organisms must have a scientific name, which is acceptable all over the world. Such naming must be based on agreed principles and criteria.
• The scientific names ensure that only one name is given to an organism and description of the organism should help the other people to arrive at the same name in any part of the world. Each kind of organism, representing a species, is given a different name to distinguish it from the other. One has to ensure that such a name has not been used earlier for any other organism. The following have been the practices of providing scientific names to the organisms:

Polynomial nomenclature

• Before 1750 (mediaval periods), scholars used to add a series of descriptive words to designate a particular species. This can be illustrated with the example of The name given was Caryophyllum saxatilis folis gramineus umbellatus corymbis meaning Caryophyllum growing on rocks having grass like leaves and umbellate corymb arrangement of flowers. Such long names cannot be easily remembered.

Binomial nomenclature:

• The scientific names were developed by Linnaeus (Philosophica Botanica, 1751). The standard references recognised for this are Species Plantarum (1753) and tenth edition of Systema Naturae (1758).
• The technical names recognized internationally are thus the ones given by Linnaeus in the 10th edition of his book Systema Naturae published in 1758. The system developed by Linnaeus is known as binomial nomenclature. Binomial nomenclature is the system of scientific naming using ‘genus’ as the first part and ‘species’ as the second part, e.g., Mangifera indica (mango), Apis mellifera (honey bee), Pisum sativum (garden pea), etc.

Trinomial nomenclature:

• Occasionally, three words are also used for naming an organism, especially the animals. These include generic, specific and sub-species part, for example, the modern man is called Homo sapiens sapiens. Other examples are Gorilla gorilla gorilla, Acacia nilotica indica, Ascaris lumbricoides humanis,

Rules Of Binomial Nomenclature

• To provide uniformity, and to avoid confusion, International Code of Botanical Nomenclature (ICBN) and International Code of Zoological Nomenclature (ICZN). The names of bacteria and viruses are decided by International Code of Bacteriological Nomenclature (ICBacN or ICBN) and International Code of Viral Nomenclature (ICVN). Similarly, there is a separate International Code of Nomenclature for Cultivated Plants (ICNCP). The important rules are:

Rules of Nomenclature

• Names are always in Latin and written in Italics. If Latin version is not available names are Latinized
• Binomial consist of genus and species name. Names of genus always start with capital letter while names of species starts with small letter. e.g.
  $$\begin{gathered} e.g. \underset{\downarrow }{Mangifera} \underset{\downarrow }{indica} \left(Mango\right) \\ genus species \end{gathered}$$
• If names are handwritten, name of genus and name of species are separately underlined.
• The name of author comes after the names of species generally written in abbreviated form in romans.  Binomial along with name of author is referred as ‘Binomial Epithet’.
• Names should not be of less than three letter and not more than 12 letters.
• If name of species consist of two words then two words are joined by putting a hyphen (–) between two words  e.g. Hibiscus rosa – sinensis   (china rose)
• Principal of priority is followed. The first validly published name is accepted as binomial and rest is considered as synonyms.
• Tautonyms are not accepted i.e. when name of genus and species are same
  e.g. Malus  malus (apple)
• Homonyms are not accepted i.e. same name of different things.
  e.g. Prunus dulsi  (Almond plum)

5.  TAXONOMIC
Taxonomic Hierarchy

• The main aim of a taxonomic study is to assign organism an appropriate place in a systematic framework of classification. This framework is called taxonomic hierarchyby which the taxonomic groups are arranged in definite order, from higher to lower categories, depending upon their relative dimensions. The hierarchy indicates the various levels of kinship. Nearer the categories in hierarchy, the greater is the similarity between their organisms.
• It is also called Linnaean hierarchybecause it was first proposed by Linnaeus. Linnaeus first used only five categories-Class, Order, Genus, Species and Variety. The last one was discarded and three added so that now there are seven obligate categoriese.,Kingdom, Division or Phylum, Class, Order, Family, Genus and Species. The botanists use Division in place of Phylum as a category in the classification of plant kingdom. In order to make taxonomic position of species precise, certain subcategories and supercategories have been added to this list and they are called intermediate categories e.g., subkingdom, super phylum or super division, sub division, super class, sub class, super order, sub order, super family, sub family, tribe, sub species, variety, etc.
• 
• Both in animals and plant kingdoms, the lowest category is Species and highest is the Kingdom. The placement of group of individuals or organisms in species, genus and upto phyla or divisions is determined by the similarities in their characters and the relationships. The categories in the hierarchy are thus in ascending order. As we go from the lowest rank Species towards Kingdom the number of similar characters decreases.
• Of various categories of classification, only the species have a real existence in nature, others are merely man made convenient and arbitrary groups without actual existence in nature. Species is regarded as the basic unit of classification.

Taxon (Gk. Taxis: arrangement)

• The word ‘taxon’ signifies a taxonomic group of any rank which represents the real biological organisms included in a category like maize (species), roses (genus), grasses (family), conifers (order), dicots (class), seed plants (division), etc.
• The term was introduced by Adolf Meyer (1926) for animal groups. H. S. Lam first proposed the term ‘taxon’ for plants.
• There is some confusion in the use of taxon and category. Bryophyta is a taxon while division is a category. Similarly Zea mays is a taxon while species is a category. Category represents an abstract term, while taxon represents the real organisms.

Obligate Categories

• The obligate categories used in classification are explained below:
• There are seven obligate categories. Sub-categories are also there to facilitate more sound and scientific placement of various Taxa.

Species

• Species occupies a key position in classification. It is the lowest or basic taxonomic category.
• It is a basic unit for understanding taxonomy as well as evolution. It is a natural population of individuals or group of populations, which resemble one another in all essential morphological and reproductive characters, carry same type and amount of genetic material so that they are able to breed freely among themselves under natural conditions in order to produce fertile offspring.
• The species is also called genetically distinctand reproductively isolatednatural population e.g., mango (Mangifera indica), potato (Solanum tuberosum), tulsi (Ocimum sanctum), lion (Panthera leo), In this case, indica, tuberosum, sanctum, and leo are species of genera Mangifera, Solanum, Ocimum and Panthera, respectively. A genus may have more than one species as in Panthera tigris where tigris is another species.
• A species may have subgroups, called subspecies or varieties, showing certain distinct features of their own.

Typological Concept of Species

• According to this concept, every species shares a common body type, any variation in that type is due to abnormalities of physical world. This is the most simple concept of species.

Morpho Species

• New species created only on the basis of morphological characters is referred as morphological species.

Taxonomical Species

• Those species which have binomial name are referred as taxonomical species.

Sibling Species

• Those species which are difficult to distinguish on the basis of morphological characters but are not able to interbreed are referred as sibling species.

Allopatric Species

• Those species which are created due to geographical isolation are referred as allopatric species.

Sympatric Species

• Species created as a result of reproductive isolation are referred as sympatric species.

Genus

• It is the first higher category above the level of species. It is a group of species which are related and have less characters in common as compared to species. For example, potato (Solanum tuberosum) and brinjal (S. melongena) though they constitute different species, belong to the same genus Similarly lion (Panthera leo), leopard (P. pardus), tiger (P. tigris) and jaguar (P. onca) have several common features and are included in the same genus Panthera.
• A genus may have a single species (monotypic), e.g., Homo sapiens, or it may have several species (polytypic), e.g., Panthera, Solanum,
• All the species of a genus have a number of common features called correlated characters. The close resemblance indicates a common ancestry for all the species of a genus.
• There is no rule for suffix in genus and species.

Family

• Family is represented by a group of related genera that are more similar to each other than with the genera of other families.
• All the genera of a family resemble one another in certain correlated characters indicating a common ancestry. The genera like Solanum, Petunia, Datura, Atropa, based on the similarities are placed in the family Solanaceae. In animals such as lion, leopard, tiger, jaguar from genus Panthera, and cat from genus Felis are included in the family Felidae.
• In plants, the family ends with the suffix – aceae and subfamily with – oidae while in animals the suffixes are ­ideae for family, – inae for sub-family, – ini for tribe (between sub-family and genus).

Order

• Order is an assemblage of families resembling one another in a few characters. These characters are less similar as compared to many genera put in a family. Families like Solanaceae and Convolvulaceae are put in the order Polimoniales on the basis of some related floral characters. Likewise, order Carnivora contains related families of Canidae, Felidae, Ursidae (bear) and Hyaenidae (hyaena).
• An order ends in suffix – ales in plants. Different suffixes are used in case of animals.

Class

• It is a taxonomic category made up one or more related orders. For example, class Mammalia has a number of orders like Carnivora, Rodentia, Insectivora, etc.
• It ends in suffixes – phyceae, – opsida and – ae in plants. The suffix is not fixed in case of animals.

Phylum Or Division

• Phylum or Division consists of one to several related classes having some similar correlated characters.
• Among the animals, the phylum Chordata includes classes Pisces, Amphibia, Reptilia, Aves and Mammals, since all classes at some stage in their lives have common characters like presence of a notochord, dorsal hollow nervous system and pharynx perforated by gill slits.
• The division is given the suffix – phyta and the subdivision – phytina.

Kingdom

• In general, it includes all organisms which share a set of distinguishing common characters. This is the highest category of biological classification. Plants are put in Plant Kingdom and animals are included in the Animal Kingdom. H. Whittaker (1969) has recognized five kingdoms of organisms-Monera, Protista, Fungi, Plantae (Metaphyta) and Animalia (Metazoa).

Table: Taxonomic Categories of some common organisms

Common Name	‘Scientific, Name	Genus	Family	Order	Class	Phylum/ Division	Kingdom
Human	Homo sapiens	Homo	Hominide	Primata	Mammalia	Chordata	Animalia
House fly	Musca domestica	Musca	Muscidae	Diptera	Insecta	Arthropoda	do
Mango	Mangifera indica	Mangifera	Anacardiaceae	Sapindales	Dicotyl-edonae	Angios-permae	Plantae
Wheat	Triticum aestivum	Triticum	Poaceae	Poales	Monocoty -ledonae	do	do

Taxonomical Aids

• Both laboratory and field studies are important for identification of various species. The information thus gathered about the species need to be stored for future studies. The actual specimens are collected, preserved and stored for verification if required later on. This helps in identification of species and their placement in taxonomical hierarchy. There are several aids like herbaria, botanical gardens, museums and zoological parks.

Herbarium

• A herbarium is defined as a collection of plants that usually have been dried, pressed and preserved on sheets. The sheets are arranged in accordance with any accepted system of classification (usually Bentham and Hooker’s system). The storage of sheets forms a repository for future use. It provides a quick refer back system and is quite useful for people involved in taxonomic studies. All institutes concerned leading with botanical studies maintain their herbaria. Students are trained to collect and identify herbarium specimens of local and distant places.

History Of Herbaria

• Majority of the world’s famous herbaria originated from the botanical gardens. The first herbarium was set up at Pisa in Italy by a professor of botany Luca Ghini. His students bound the paper sheets having plant specimens mounted on them into book volumes, and spread the art of herbarium throughout Europe.

Herbarium Technique

• For collection of specimens, one has to carry certain simple tools such as digger for digging roots, a scissor for cutting twigs, knife for woody twigs and a pole with hook for collecting parts of tall trees.
• Vasculum and polythene bags are used to temporarily store fresh shoots to avoid loss of moisture and distortions by drying and shriveling up. Vasculum is a box of 45-60 cm length, 20 cm width and 25 cm depth.
• Succulent parts, fruits, tubers, rhizomes are preserved in bottles having FAA (formalin + acetic acid, alcohol). Some of them can also be dried and kept in packets.
• Care is to be taken to ensure that in the case of herbs, both vegetative and reproductive parts are there in the collected plant specimen. However, twigs with leaves, inflorescence and flowers are collected from the shrubs and trees.
• Generally sufficient number (5-6) of individual specimens of a particular kind are collected. This is necessary in case of damage during the process of transport and preservation. The specimens are referred to by the assigned collection number, which are called the field numbers.
• The specimens are spread out, in shortest possible time. They are dried by keeping them between the folds of old newspapers. It is necessary to change these papers at regular intervals to avoid fungal growth. Complete specimens with all parts are dried in a plant press. The plant press consists of a set of two boards with straps, which help in tightening the newspaper sheets with specimens between the boards.
• The bigger specimens are not cut but they are folded generally in now form. Some leaves are spread for showing dorsal surface and others to show ventral surface.
• The dried specimens are pasted on the herbarium sheets of standard size (41×29cm). Specimens before fixing are kept upside down on paper sheet, glue or adhesive is applied and then they are mounted on the herbarium sheet.
• All the pasted specimens are sprayed with fungicides like 0.1 % solution of mercuric chloride, pesticides like DDT, naphthalene and carbon disulphide to check the growth of fungi.
• The heavy parts of plants like seeds fruits are put in a packet and attached to the sheets.
• Label (7×12 cm) is pasted over the right hand corner and carries the following information:

Collection Number

• Place/Locality
• Name of Collector
• Date and Time
• Common English Name
• Vernacular Name
• Scientific Name
• Family
• Institution
• The information about the specimens is compiled and published in a form of a book (flora), which gives a list of total plant species in a particular region, country or continent together with a brief description.
• There are several floras in India such as Flora of British India (J. D. Hooker), Flora of Delhi (J. K. Maheshwari), Flora Simlensis (H. Collet), Flora of Bombay (T. Cook), Flora of Bihar and Orissa (H. H. Hains), Flora of Bengal (D. Prain), Flora of Mussorie (M. B. Raizada and H. O. Saxena), etc.

Major Herbaria

• Largest herbaria of the world are at Royal Botanic Gardens, Kew, England (6.5 million specimens) and Museum of Natural history, Paris (6 million specimens). In India, the largest herbarium is at Indian Botanical Garden, Kolkata, called Central National Herbarium (2 million specimens).

Role Of Herbaria

• Repository of plant specimens
• Safety of type specimens
• Compilation of Flora, Manuals and Monographs
• Identification facility
• Preservation of voucher specimens
• Knowing ecology of different places.

Botanical Gardens

• Botanical gardens are collections of living plants maintained for reference. It is considered natural and economical reference system. There are over 525 large size botanical gardens developed in the various parts of the world. A botanical garden exclusively growing trees and shrubs is called
• The most famous and the largest botanical garden is Royal Botanical Gardens, Kew (London), England. It is extended in 200 acres of land. It was founded in 1759 by William Aiton.
• The largest botanical garden of India is Indian Botanical Garden, Howrah (Sibpur), Kolkata. It was established in 1787. Besides it, other main botanical gardens are:
• National Botanical Gardens, Lucknow.
• Lloyd Botanical Gardens, Darjeeling.
• Garden of the Indian Agriculture Institute, Dehradun, etc,
• A botanical garden usually houses a library, laboratory, herbarium and museum. It frequently offers teaching and training facilities also.
• In botanical gardens, one may find each plant in the garden with scientific name and family mentioned on the label.

Role

• Provides plant material for comparative taxonomic studies.
• Functions as acclimatization centre for exotic plants of economic importance.
• Provides materials for botanical research.
• Ex-situ conservation of endangered plant species.
• Improve the environment, provides greenery in big cities, purify the air, and serve as habitat for many animals.

Museums

• Museums have collection of preserved plants and animals for study and reference. Only those plants are preserved in museum which cannot be kept in herbaria, e.g., algae, fungi, mosses, ferns, parts of gymnosperms, fruits, underground storage organs, etc. Animals are preserved in chemical solutions (mostly formalin) as well as in stuffed and skeleton forms.
• The collected specimens are correctly identified and labelled. They are stored and a catalogue is prepared for future reference.
• The objective of preparing a museum is to record information and preserve specimens for taxonomic studies.
• Collection of preserved plants and animals for study and reference.
• Specimens are preserved in containers and Jars in preservative solutions.
• Insects are preserved in insect boxes after collecting, killing and pinning.
• Birds and mammals are usually stuffed and preserved.
• Museum also have collection of skeletons of animals.

Role

• The collection of specimens helps in gathering the first hand information about the habitat, soil and organisms of the area.
• They are used to deposit type specimens whenever new taxa described.

Zoological Parks

• An enclosed place where live wild animals are kept for public exhibition is called a zoological park.
• Zoological parks provide more natural environment.
• The scientific purpose of the zoo is to breed the animals which otherwise are facing a threat in their natural habitat. Due to development activities, they are facing poaching and habitat destruction.
• Information about common name and a scientific name is also displayed in the zoological garden park.
• Places where wild animals are kept in protected environment under human care.
• Food habit and behavior of animal is studied.
• Condition of zoo is more or less similar to natural habitat of animal.

Role

• Study of live animal types.
• Sources of tourist attraction.
• Ex situ conservation through captive breeding of endangered animals.

Keys

• A scheme for identification of plants and animals is known as The term key refers to a set of alternate characters arranged in such manner that helps in the identification of an organism by selecting or eliminating the characters according to their presence or absence in the organisms. Thus, taxonomic keys are based on the contrasting characters generally in a pair called couplet. It represents the choice made between two opposite options. The results in acceptance of only one and rejection of the other. Each statement in the key is called a lead.
• Separate taxonomic keys are required for each taxonomic category like family, genus or species. These are more useful in identification of unknown organisms.
• Being analytical in nature these are generally of two types, yoked or indented and bracketed.
• The indented key provides sequence of choice between two or more statements of characters of species.
• The user has to make correct choice for identification. In a bracketed key the pairs of contrasting characters are used for identification and they are given numbers in brackets. The numbers on the right indicate the next choice of paired contrasting characters.
• Example: Five genera of family Ranunculaceae (Clematis, Narvelia, Anemone, Nigella and Aconitum) are to be identified by using the following indented and bracketed keys, separately, by considering the characters of carpel, fruit, floral characters and leaves of the specimens. The first choice starts with carpel with single ovule and achene type of fruit in contrast to carpels being many ovuled and fruits being follicles.

Other Taxonomic Aids

• Other taxonomic aids are monographs, manuals, publications, etc.
• Monographs give comprehensive account of complete compilation of available information of any one family or genus at a given time.
• Manuals contain compiled information about area covered, keys, and description of families, genera and species.
• Publications like periodicals and dictionaries are brought out to provide information about new additions and updated information.
• Flora contains the actual account of habitat and distribution of plants of a given area. These provide the index to the plantspecies found in a particular area.

Types Study

• Holotype or Nomenclature Type: Material selected by author to name the plant is known as holotype.
• Isotype: Duplicate of holotype is known as isotype.
• Paratype: Any specimen described by author along with holotype is known as Paratype (it has some unique character).
• Syntype: Where there is no designated holotype and nomenclature is done on the basis of two or more than two specimen. They are referred as Syntype.
• Lectotype: When holotype is missing then other material form original collection is selected to serve as a holotype is known as lectotype.
• Neotype: New material collected to serve as holotype when original material are missing.
• Topotype: When new material is selected / collected from same locality from where holotype was collected it is known as Topotype.